PHOTO

The body is opaque white, with translucent orange oral tentacles and a black [or dark brown] band across the front edge of the head. The gills and rhinophores are translucent clear with orange edgings and the extra-branchial and extra rhinophoral processes are opaque white.

Gosliner & Fahey emphasise the uniqueness of an "elevated hump anterior to the gill" naming the species 'gibbera' from 'the Latin word meaning 'a hump on the back'. To me it looks like the pericardial hump found to varying degrees in all species. In my experience this 'hump' can sometimes be raised and sometimes flattened in an individual so may not be a useful character.